The invention relates to an electric parking brake for a motor vehicle. In particular, the invention relates to a technique for safely releasing the parking brake.
In known variants of electric parking brakes, a parking braking force is either effected by means of an electromechanical element, e.g. an electric motor having a self-locking reduction gearing or, for example, is built up electrohydraulically and held by means of an electromechanical element. Electric parking brakes are usually actuated and released by a driver of the motor vehicle, by means of a switch or pushbutton. Provision of a switch or pushbutton, however, is conducive to inadvertent release of the parking brake, as a result of which accident damage can be caused. For example, the parking brake can be inadvertently released by the driver himself as he gets out of the vehicle, or also, for example, by playing children or by animals.
Various methods are known for preventing inadvertent release of a parking brake. Usually in such methods, presence of a driver of the motor vehicle is deduced from a combination of signals from the environment of the motor vehicle, and release of the parking brake is then rendered possible only if presence of the driver has been identified. Thus, DE 101 53 038 B4 proposes a control for an electric parking brake that evaluates the various signals in order to control a release of the parking brake. In addition to a signal that indicates a driver's wish to release the parking brake, the ignition of the motor vehicle must be switched on, while a service brake of the motor vehicle is active or its state is not determinable.
The invention is based on the feature of specifying a technique that provides improved protection against inadvertent release of an electric parking brake of a motor vehicle.